Norwegian 4x4 workout

Interval Training Timer

Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.

A private interval timer for the Norwegian 4×4 protocol — live heart-rate zones on iPhone and Apple Watch, plus workout history and VO₂max trends. Norwegian 4x4 is a focused interval training timer for the proven Norwegian 4x4 protocol — four 4-minute high-intensity intervals with 3-minute active recovery periods.

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Your Norwegian 4×4 workouts now build a picture of your fitness over time. WORKOUT HISTORY & DETAIL Every workout is saved with full heart-rate detail. Tap any session to see your heart-rate curve with each phase shaded, a per-interval breakdown, and your time in the target zone. FITNESS TRENDS A new trends dashboard shows where you're heading — your heart-rate recovery after each interval and your average interval heart rate, each with a sparkline and a week-over-week trend — plus your weekly workout count and current streak. POST-WORKOUT SUMMARY See your duration, peak heart rate, and average heart-rate recovery the moment you finish. MORE RELIABLE APPLE WATCH SYNC Live heart rate stays current on your iPhone even with your wrist down, and starting a workout on one device keeps the other in sync. YOUR DATA, YOUR CONTROL All history is stored privately on your device. Delete any single workout, or clear your whole history, at any time.

The developer, Alice Winthrop, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Seller
    • Alice Winthrop
    Size
    • 34.3 MB
    Category
    • Health & Fitness
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    • Mac
      Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    • Apple Watch
      Requires watchOS 10.0 or later.
    Languages
    • English
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    • © Alice Winthrop 2026